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list
The list command determines the number and types of video and audio inputs.
Digital-video and VCR devices recognize this command.
wsprintf(lpstrCommand, "list %s %s %s", lpszDeviceID, lpszList,
lpszFlags);
Parameters
lpszDeviceID
Identifier of an MCI device. This identifier or alias is assigned when the
device is opened.
lpszList
Flag that identifies the number and types of video and audio inputs. The
following table lists device types that recognize the list command and the flags used by each type:
digitalvideo
| audio algorithm
audio quality algorithm algorithm
audio stream
count
number index
| still algorithm
still quality algorithm algorithm
video algorithm
video quality algorithm algorithm
video source
video stream
|
| audio source count
audio source number index
| - ideo source count
video source number index
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The following table lists the flags that can be specified in the lpszList parameter and their meanings:
audio algorithm
| Specifies the command should retrieve audio algorithm names.
| audio quality algorithm algorithm
| Specifies the command should retrieve quality levels associated with the
specified algorithm. If algorithm is "current", the quality level of the current algorithm is returned.
| audio source count
| Returns the total number of audio inputs.
| audio source number index
| Returns the type of audio input of source index.
| audio stream
| Specifies the command should retrieve the names of the audio streams
associated with the workspace. These strings (such as "English" or "German") are
embedded in the file and identify the stream.
| count
| Returns the number of options of the specified type.
| number index
| Returns a string describing a specific option (as identified by index) of the specified option type. Index must be an integer between 1 and the value returned by "count".
| still algorithm
| Specifies the command should retrieve still algorithm names.
| still quality algorithm algorithm
| Specifies the command should retrieve quality levels associated with the
specified still algorithm. If algorithm is "current", the quality level of the current algorithm is returned.
| | Specifies the command should retrieve video algorithm names.
| - ideo quality algorithm algorithm
| Specifies the command should retrieve quality levels associated with the
specified video algorithm. If algorithm is "current", the quality level of the current algorithm is returned.
| | Specifies the command should return information about the video sources. When
used with the "count" flag, it returns the number of video sources. When used
with the "number" flag, it returns the type of a video source. MCI defines the
following constants for type: "ntsc", "rgb", "pal", "secam", "svideo", and
"generic". There might be more than one source of each type returned. The "generic"
source type is used when more than one signal is allowed for that connector.
| | Returns total number of video inputs.
| | Returns the type of video input of source index.
| | Specifies the command should retrieve the names of video streams associated
with the workspace. These strings (such as "funny ending" or "sad ending") are
embedded in the file and identify the stream.
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lpszFlags
Can be "wait", "notify", or "test". For more information about these flags,
see The Wait, Notify, and Test Flags.
Return Values
Returns zero if successful or an error otherwise.
Remarks
For VCR devices, either "video source" or "audio source" must be specified
with either the "count" or "number" flags. If "count" is specified, the total
number of inputs of video or audio is returned. If "number" is specified, the
driver returns a type corresponding to the input. The type can be any one of the
following: "tuner", "line", "svideo", "aux", or "generic". Typically, you should
first query the VCR for the "count" and then use the count as the range for the
"number" flag. The "source" numbers start from 1.
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